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Gradual demise of a thin southern Laurentide ice sheet recorded by Mississippi drainage.

التفاصيل البيبلوغرافية
العنوان: Gradual demise of a thin southern Laurentide ice sheet recorded by Mississippi drainage.
المؤلفون: Wickert AD; Institute of Arctic and Alpine Research and Department of Geological Sciences, University of Colorado, 1560 30th Street, Boulder, Colorado 80303, USA., Mitrovica JX, Williams C, Anderson RS
المصدر: Nature [Nature] 2013 Oct 31; Vol. 502 (7473), pp. 668-71.
نوع المنشور: Historical Article; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.
اللغة: English
بيانات الدورية: Publisher: Nature Publishing Group Country of Publication: England NLM ID: 0410462 Publication Model: Print Cited Medium: Internet ISSN: 1476-4687 (Electronic) Linking ISSN: 00280836 NLM ISO Abbreviation: Nature Subsets: MEDLINE
أسماء مطبوعة: Publication: Basingstoke : Nature Publishing Group
Original Publication: London, Macmillan Journals ltd.
مواضيع طبية MeSH: Ice Cover* , Rivers*, Seawater/*analysis, Freezing ; Gulf of Mexico ; History, Ancient ; Mississippi ; Models, Theoretical ; Oxygen Isotopes/analysis
مستخلص: At the Last Glacial Maximum (LGM), about 21,000 years before present, land-based ice sheets held enough water to reduce global mean sea level by 130 metres. Yet after decades of study, major uncertainties remain as to the distribution of that ice. Here we test four reconstructions of North American deglacial ice-sheet history by quantitatively connecting them to high-resolution oxygen isotope (δ(18)O) records from the Gulf of Mexico using a water mixing model. For each reconstruction, we route meltwater and seasonal runoff through the time-evolving Mississippi drainage basin, which co-evolves with ice geometry and changing topography as ice loads deform the solid Earth and produce spatially variable sea level in a process known as glacial isostatic adjustment. The δ(18)O records show that the Mississippi-drained southern Laurentide ice sheet contributed only 5.4 ± 2.1 metres to global sea level rise, of which 0.66 ± 0.07 metres were released during the meltwater pulse 1A event 14,650-14,310 years before present, far less water than previously thought. In contrast, the three reconstructions based on glacial isostatic adjustment overpredict the δ(18)O-based post-LGM meltwater volume by a factor of 1.6 to 3.6. The fourth reconstruction, which is based on ice physics, has a low enough Mississippi-routed meltwater discharge to be consistent with δ(18)O constraints, but also contains the largest LGM North American ice volume. This suggests that modelling based on ice physics may be the best way of matching isotopic records while also sequestering enough water in the North American ice sheets to match the observed LGM sea level fall.
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المشرفين على المادة: 0 (Oxygen Isotopes)
تواريخ الأحداث: Date Created: 20131101 Date Completed: 20131211 Latest Revision: 20211021
رمز التحديث: 20221213
DOI: 10.1038/nature12609
PMID: 24172978
قاعدة البيانات: MEDLINE
الوصف
تدمد:1476-4687
DOI:10.1038/nature12609